Turbine rotor for turbojet engines



Nov. 3, 1953 R. M. WILLIAMS TURBINE ROTOR FOR TURBOJET ENGINES 2 Sheds-Sheet 1 Filed Dec. 17, 19 .47

Nov. 3, 1953 R. M. WILLIAMS 2,657,902

TURBINE ROTOR FOR TURBOJET ENGINES Filed Dec. 17, 1947 2 Sheets-Sheet 2 INVENTOR.

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Patented Nov. 3, i953 musing; m 0m. in m The-invention relaxes gen'erallys to. tum torconstmctiom and more; its abinelr otor fonai turbo-jetengine The general: objectof the invent-ion;- issto; 19110:; vide' a,- turbines notes for a" burbosjeb engine havingblades secured: tothe notom body in anovelmannen to provide adequate suppers; to); the bladesagainstr'thes forces tomb-10h; they: are subjected-5 Another object is to provide-a novel mmms.

roton having-hol1ow1-blades mountedon the; pee niphery of? the rotor body, with provision made in the structure for--se zuring the; blades. to. the rotorbody; so bhat" cooling alir wil'l be supplied. throughthe rotor-= bodyto such sbmcturefand to the blades themselves, to psevemoverheating thereon by the combustion gases to which thebladesare subjected-a (when obj ectsand' advantages wili become ape. parent from the following desei iption takers in connection with the accompanying-swings, in which:

Figure- 1- is a perspecshze View of a tusbine rotor embodying; the features ofi-thesinvention Fig. 2* is a, fragmentary transverse sectional viewof the rotor-shown in Fig; I, the section being taken in an axial planeextending through one oi the blades; as indicated by the line. 2-2 of Fig;

Fig. 3 is a view similar to aportion okFig. 2 but with the section taken in. an axial plane extending between the blades Fi 4 is a. fra mentary sectriQnal View; tslsm qnlthe y e. 4n=4g ;-"fi .s-v3,'-.

E s. 5 s a l msmsnkarr iew s m s n snand. sken. .11- th i-1e 9 E151,

I The ur n r s: oi t e resent a utiq ad p e t tur l mv of he g s; nw- Whi e as tu bine m y av man i rent, is the pr sen i tansze he ux-b n is: s im?! mm: s FEW-1 1 .13: dapt d" r n a, hubs: i i n ne In an; engin of sunset-es, the turbine. otor, s sub ect d, to,- :4V ews: stream. Q ho ga es lqwi s mm s comb i ichem: h r are this ngine he tuz a p r on. of the nergy in. he. pgws: stream; n uti i s u h en rgy 4Q ives. sqmn sqn is: delivering, i n t e qmlmst sn ch ms ecause of he high Q QQQZTQ BEQ 915 the mm;

s ream o. wniqh names we th b sqqs Q; 2 1% A,

urbin r tor are subi tsq... and. Manse 92 t e h h tative. sh et .1, the. mm... 1.9 91 swim desirable to provide a maximum strenggh for mi mum weight in. t e eriph ral; lierfiq mm:.. .1: sle lmhle is mat sis P1 sm ms 2; he w ib k the a es welt as thfir'blmas cool possiblev so? lossloi' stmngih in, them iall prising the. biz-ides; and mm due n a r t m odsine the paesentg inxemiql-in a? m, is psovided; which is te geceiyol in. a, cavits in the central: porticn thfifiez. on a fluid; such as air taken ngoml ambienq atmosphere. Radial: passages are pm; vided; in theroton body forthe air to, the-.pe iphqryv thereok The. turbine. blades, oi} course, else car-sled on the p z iphesy on the 1 0-; to and, in: the, instane, aresmade hollow so this the sire delivered through such redi passages may be conducted mainly Qhrough'theblades to maintain motel theses of at as low a tgqmp egqtuge as possibleby cans vying om the hemr by the blades f-zom the power streapi. *Qhe igurbine rotoi rotates at a, mi i-lively high speed; so that-- the sta essesf at the perlphjerybfythe rotgn where the hlades are, connected t hereqo, are rely/l vely great The problem is, the gefoz e, qdequately secure the blades tn}. the peniphery- 01 the'rotori and; at the s m e. b 6 39 F m lfl hrou he b d e e -1mm 1 M 2 Oi the robe;- also heing coo ed t 'maimag the des redr mns e m With lghe' present invention, a plenum chamher is pmvidfed in ghg: pegipherdl portion of the TQQOIF, which receives aiifi through the redial passagesfin the. rotor body and conigiunicates'ivith the injseriop' I- the blades so the; maximum ooolm 15 ms di s dads a ed is mq nt l n, 't s she h 'r 'b i th ini zior ihwh s r q q 'z wi h a s 9m 2 42 i the lwfl is, i l h s pso qe i122 qhsmflsr: 3% ades a i nq a .9 Wis es. m. mqq i "1% s 2! n as weeding; 1 m. he iqrrbs yi .e i-

51.71% as: th n sew d; we #9 ins. rqios hes-x and @9- he mm ins -29 hsi he are 25 new; s 4 we; assi n: displsqsmszst- R 239 213? ps Quest q xsslatie or, sis the 21. seamless the Ewe! ga ssss sis m israplx s: wa es In sihs ami l al msm, with t e biflss .1m the blades a}, heir; suds wi l mv k ed with circumferentially opening note so W 1. 5%! as well as, ssiwss ls thmss he b ade; slim say we; same 2! ki ls maths the 9i wee! is 2995 body. The shroud ring, which preferably has a U-shaped cross section, is first shrunk on the rotor body and is welded thereto at both faces of the rotor body, that is, to the peripheral edge portions of the rotor body formed as a result of the groove cut in the periphery of the body. The shroud ring is thus rigidly secured to the rotor body and may be said to constitute an integral part thereof, and by this method of attachment the plenum chamber may be readily formed. When the blade-receiving notches are cut, the shroud ring is severed into a series of segmental shroud members, since the notches extend inwardly into the rotor body proper. The blades, whose inner end portions substantially close the notches, are then welded both to the rotor body and to the edges of the shroud members at the lines of meeting of the blades therewith.

In the embodiment shown in the drawing, the

rotor body is indicated at l and may be said to be generally. of disc-shaped form. At one side of the rotor body III, a hub portion II is. provided which, in the present instance, is shown as telescoping within a tubular shaft l2 and is welded thereto as at IS. The tubular shaft may receive air from the ambient atmosphere or from. the compressor and provides a conduit for conducting the air to the interior of the rotor body Hi, the body being provided with a central cavity H for receiving such air. Extending from the cavity I4 is a plurality of radial air-conducting passages |5 for carrying the air to the periphery of the rotor. To provide a plenum chamber for the air in the peripheral portion of the rotor body, a circumferential groove. IB is cut therein. The groove l6 thus-provides a pair of axially spaced edge portions IT on the periphery of the ring. The outer corners of the edge portions |1 may be beveled as at 20 for welding purposes, as will be hereinafter described. To complete and enclose the plenum chamber, a shroud ring 2| of generally U-shaped cross section is mounted on the periphery of the rotor body I0. Such shroud ring thereby cooperates with the groove IS in the rotor body to form the plenum chamber. The arms of the U extend inwardly and, in the present instance, are preferably made at their edges of substantially the same width as the edge portions ll of the rotor body Ill. The outer corners of the edges formed by the arms of the U are beveled as at 22 in a manner similar to the bevel 20 on the rotor body to form a generally triangular groove in the outer face of the rotor. In securingthe shroud ring 2| in place, it is preferably first shrunk onto the rotor body so that the edges .formed by the arms of the U are in tight contact with the edge portions ll of the rotor body. The shroud ring is then weldedin place and weld metal 23 is filled into the triangular groove formed by the bevels 20 and 22. The shroud ring 2| thus becomes substantially integral with the rotor body |0 but with a plenum chamber therein formed by the groove It in the interior of the shroud ring. This hollow construction provides distributed support for the turbine blades without disturbing the smoothness of the gas passages. It also permits using a heat resistant material in the area exposed to the hot gases with the same or a different material for the body of the rotor.

The next step in making the complete rotor is to prepare the rotor body and shroud ring for insertion of the turbine blades. In the present instance, each turbine blade comprises a portion 24 projecting'beyond'the periphery of the shroud ring and a shank portion 25 inserted within the rotor body and shroud ring for rigidly holding the blade in place, both portions being hollow with a blade opening at each end. To provide for insertion of the blades, a plurality of notches 26 are cut in the periphery of the rotor to receive the shank portions 25. While the notches 28 extend generally transversely to the plane of the rotor body, they may be curved and at a slight angle, as shown in Fig. 4, so that the shank portion 25 may conform generally to the position of the outer portion 24. In the preferred form of blade utilized, the shank portion 25 has a width substantially equal to the thickness of the rotor body at the periphery thereof, as is clearly shown in Figs. 2 and 3. The notches 26 are of sufficient depth to extend inwardly beyond the shroud ring and into the rotor body itself, thereby severing the shroudring into a plurality of segmental shroud members lying between the respective blades. The surface of the shroud ring and rotor body where the notches intersect such surfaces are beveled, as at 21, for welding purposes except for the peripheral face. The inner ends of the shank portions 25 are beveled as at 30, while the rounding of the side edges of the shank portion, as indicated at 3| in Fig. 4, provide triangular spaces with the beveling of the shroud members and rotor body for the placement of weld metal. The shank portion 25 is then welded both to the shroud members and to the rotor body at the lines of meeting with the outer surfaces thereof, and the triangular grooves formed by the bevels 21 and 30 and the rounding of the edges of the shank portion 25 are filled with weld metal 32 to provide smooth faces where the shank portion 25 meets the side faces of the rotor body and shroud members. Such welding rigidly secures the blades in place and completely closes the plenum chamber in the periphery of the rotor .body.

To facilitate the welding process, it will be noted that the edge portions of the shroud ring 2-| are of substantially the same cross-sectional area as the edge portions ll of the rotor body. f'he thickness of the wall of the hollow blades is also commensurate with the sections to which it is welded so that uniformity of weld is attained at such parts, as well as between the shroud ring and the rotor body.

As to the cooling action, the radial passages l5 of the rotor body are preferably substantially aligned with the inner ends of the blades so that cooling air may be conducted directly thereto. However, the plenum chamber formed by the groove I6 and the shroud members also receives air since the groove It extends inwardly beyond the inner ends of the blades, as is apparent in the drawing. To facilitate circulation within the plenum chamber, the shank portions 25 of the blades are provided with notches 34 opening circumferentially within the plenum chamber, so that adequate communication between the radial passages IS, the plenum chamber, and the interior of the blades is thereby provided.

With the structure described, the blades are adequately supported against the stresses to which they are subjected. Moreover, the structure provides for sutlicient cooling both of the blades and of the peripheral portions of the rotor sothat undue loss of strength of the parts due to high temperatures is not incurred.

I claim:

A turbine rotor for a turbo-Jet engine, comprising a generally disc-shaped rotor body having a series of circumferentially spaced notches in its periphery with the notches opening at both faces of the body, a plurality of turbine blades having shank portions located in said notches, each shank portion having a width substantially equal to the thickness of the rotor body at said notches, welded joints cooperating between the shank portion and the rotor body along the lines of meeting of the shank portion with the faces of the rotor body, and shroud members located between the shank portions of the blades and constituting an extension of the rotor body, said shroud members being formed of a heat resistant metal, welded joints between said shroud members and the body at the lines of meeting of the shroud members with the faces of the rotor body and welded joints between said shroud members and the shank portions along the lines where the exterior surface of the side faces of the shroud members meet the shank portions.

ROBERT M. WILLIAMS.

References Cited in the file of this patent UNITED STATES PATENTS Number 5 1,229,490 1,470,506 1,657,192 2,038,670 2,143,466 10 2,264,877 2,354,304 2,393,963 2,432,185

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